A study on water and sustainability for power production in the US by the Electric Power Research Institute compared the water needs and consumption rates of existing power stations by type of fuel and cooling technology. The EPRI analysis showed that existing nuclear power stations used and consumed significantly more water per megawatt hour than electricity generation by fossil fuels. Nuclear 'oncethrough' systems use about 20-25% more water and nuclear 'closed systems' can use up to 83% more water.